Elderly NHS patients are suffering after new figures showed that 90% of primary care trusts are restricting treatment in response to financial pressures, Labour's deputy leader Harriet Harman has claimed.

Harman cited the example of an elderly patient who was told they could only have surgery in one eye even though they had cataracts in both eyes.

Harman highlighted a report by GP Magazine and a survey by Labour which disclosed that 125 separate treatments have been restricted or stopped altogether by the NHS, as she challenged William Hague over the cuts at prime minister's questions.

The foreign secretary was standing in for David Cameron, whose absence due to the G20 summit in Mexico meant that by convention Ed Miliband also missed the weekly session.

"How can you justify an elderly person with cataracts in both eyes being told they can only have surgery in one of them?" Harman asked Hague. "What do you say to an elderly patient who needs a hip replacement? Wait in pain or try to pay and go private?"

The foreign secretary said health trusts in England have been told they are not allowed to ration services on cost grounds, as he accused the last Labour government of "arbitrarily restricting access" to operations. "The NHS medical director has written to trusts to tell them the only criteria of decision must be clinical and not financial," he said. "If evidence is found that they are ignoring that then the secretary of state can intervene. The department of health will look into any cases where they are using financial conditions."

Hague challenged Harman to condemn Thursday's planned strike by doctors as he highlighted comments made by Diane Abbott, the shadow public health minister, expressing sympathy for them. Harman said: "We don't want patients to suffer so we don't want the GPs to be going on strike."

She highlighted the cuts to NHS care shortly after Andy Burnham, the shadow health secretary, published a survey by the party showing 125 treatments which had been provided free have been restricted or stopped altogether by the NHS in the last two years. Labour surveyed all English NHS primary care trusts and the shadow clinical commission groups that will take over commissioning powers under the government's health reforms.

The Labour survey echoed findings by GP Magazine. Freedom of information requests by the magazine found that primary care trusts have restricted hip, knee and cataract operations to save money.

Burnham cited the example of a GP surgery in Haxby, North Yorkshire, which sent a letter to patients awaiting minor operations saying that the practice would no longer commission the care. The practice then said it had launched a private practice for minor operations and included a price list for wart and skin tag treatments.

Burnham said: "In some cases there is a worry here that the decisions to restrict treatment is opening up a private market for those same commissioners. We feel that could be fatal for public trust in the NHS. The government urgently needs to clarify its position on that."

The shadow health secretary blamed the cuts on the so-called "Nicholson challenge" – the need for £20bn in savings – and the government's health reforms, which will devolve most of the NHS's £100bn budget to new GP-led commissioning bodies. "We are presenting new evidence of crude, random rationing across the NHS in England, going far wider and deeper than yesterday's reports suggested," he said. "Right now a postcode lottery is running riot through the NHS in England, a major acceleration in the two years since the general election, and exactly what we warned would happen when the government brought forward its reorganistion."

Harman used the first session of PMQs since Cameron gave evidence to the Leveson enquiry to roll out some pre-prepared jokes at his expense. Citing a pre-election article on midwives the prime minister wrote for the Sun, she said he had written for the News International title "because professionally, of course, they were are all in it together".

The deputy leader added: "Before the election the leader of the opposition was all 'yes we Cam', as soon as he became prime minister it's 'no we can't'. The prime minister once told us he could sum up his priority in three letters: NHS. Isn't it more like LOL?"

Hague, who was answering PMQs for the first time in a decade, joked: "It obviously took a long time to think of that one."